Biological complexity: photosynthesis (Introduction)

by David Turell , Saturday, February 27, 2016, 15:32 (3192 days ago) @ David Turell

This is a highly complex mechanism which protects itself from the oxygen produced:-https://www.sciencedaily.com/releases/2016/02/160226143945.htm-"Photosynthesis takes place in stages. In the 'first stage' light is absorbed and used to produce energy molecules, with oxygen as a byproduct. These energy molecules are then used to power the 'second stage' of photosynthesis, in which carbon dioxide from the air is fixed into carbon-based sugars, such as glucose and sucrose.-***-"The team was able to figure out that at least one aspect of CGL71's job is to protect the photosynthetic apparatus from oxygen during its assembly. Yes, that's right, from oxygen. You see, photosynthesis first evolved in bacteria about 3 billion years ago, a time when the Earth's atmosphere had very little oxygen. Of course, as photosynthetic bacteria became more and more populous on ancient Earth, the atmosphere changed, eventually creating the oxygen-rich air that we breathe today.-"Oxygen is a very reactive molecule that can disrupt the iron-and-sulfur-containing clusters of proteins that are crucial to photosynthesis. Like CGL71, these clusters are critical for the first stage of photosynthesis, where they move electrons in order to create the energy molecules. Just as oxygen can rust iron that makes up a horseshoe or frying pan, it can damage the iron-and-sulfur proteins of the photosynthetic apparatus.-"So as oxygen accumulated in the Earth's atmosphere, the photosynthetic mechanism needed protection from its own byproduct, and CGL71 is one component that evolved to keep the photosynthetic apparatus stable under these new conditions."-Comment; Any aspect of life's chemistries is complex. Photosynthesis also has ben shown to have quantum mechanics as part of the reaction. (Friday, June 21, 2013, 15:06)